I have been running Schaeffer synthetic supreme 9000 5w40 combined with an FS2500 by-pass filtration system for a couple years now. Started doing oil analysis to see how far I could safely extend my drain intervals. The first few everything was normal. After this last oil change, I sampled at 10,000 miles. The report came back normal, suggested to sample again in another 10,000. A couple thousand miles later, I sent a sample to Schaeffer's to test (I got a free one from a friend). The other samples were done by another company(Stavely) through the filter manufacturer. The report from Schaeffer showed iron at 205 ppm and soot at 2%. The viscosity was increased to abnormal levels and they recomended an immediate oil change and resample. Is the iron level something I should be worried about? Why the soot loading and thickening even with filtration that's supposed to remove it? I don't understand how the two reports could differ so much in only 2000 miles.